"Frost/Nixon" is an effective, straightforward bigscreen version of Peter Morgan's shrewd stage drama about the historic 1977 TV interview in which Richard Nixon brought himself down once again.

“Frost/Nixon” is an effective, straightforward bigscreen version of Peter Morgan’s shrewd stage drama about the historic 1977 TV interview in which Richard Nixon brought himself down once again. Like the other election-year release about a modern Republican president, “W.,” this one isn’t out to “get” its much-vilified subject as much as to cast him as something of a tragic victim of his own limitations and foibles — tragic for the perpetrator and his country alike. Frank Langella’s meticulous performance will attract serious filmgoers, assuring good biz in upscale markets, but luring the under-40 public will pose a significant marketing challenge. Universal release preemed Wednesday night as the opener of the London Film Festival in advance of its Dec. 5 Stateside bow.

Re-creating his Tony-winning role, Langella doesn’t instantaneously convince as the 37th president the moment you first see him, in the wake of Nixon’s resignation in disgrace on Aug. 9, 1974 — the voice seems a bit languorous, the mannerisms a tad forced, his features a shade Mediterranean. But over the course of the piece, the many facets of the performance merge into an impeccably observed characterization of a man whose accomplishments, intellect and aggressive use of power never entirely overcame an abiding inferiority complex and propensity for self-sabotage.

Morgan, who has carved a unique niche for himself penning smart dramas about the private dealings of eminent modern figures (“The Queen,” “The Deal,” “The Last King of Scotland”), laid out in his 2006 play the unlikely circumstances surrounding Nixon’s four-part interview with English TV personality and chatshow host David Frost (Michael Sheen), a breezy entertainer better known for bantering with showbiz stars than for confronting political heavyweights.

As with “The Queen,” one couldn’t have suspected there was necessarily a film in this material or, even if there were, that it could be written with such authority and seeming inside knowledge. In this case, the important events unfolded much as they do onscreen: The bold and opportunistic Frost, then hosting a TV show in Australia, put his own money on the line to keep the project alive when all the major networks and most advertisers shied away from the checkbook journalism involved; Swifty Lazar brokered the deal that would bring Nixon a much-needed $600,000; the former president saw the epic interview as a means of rehabilitating himself, which in turn would lead to a move back East to the corridors of power; and, in what was mutually acknowledged to be a duel in which only one man would prevail, Nixon almost effortlessly controlled the interview until Frost turned the tables in a desperate, last-minute ploy.

Although it all pays off in a potent and revelatory final act rife with insights into the psychology and calculations of power players, the initial stretch is rather dry and prosaic. Perhaps needlessly adopting a cinematic equivalent of the play’s direct-to-audience address, Howard “interviews” several of the characters, witness-style, which makes the film feel somewhat choppy, half like a documentary at first. Approach also imposes an overly predictable editing style on the whole film, one in which the cuts come precisely on the expected beats, when a fleet, syncopated rhythm would have moved the exposition along with more flair. The film might even have done without the talking heads altogether.

Sheen, so effective as Tony Blair in both “The Deal” and “The Queen,” excels again as Frost, an insouciant ladies’ man who in many ways was Nixon’s opposite — light, devil-may-care and sociable rather than dark, brooding and awkward. An engaging early scene — in which Frost, traveling with recruited British producer John Birt (Matthew Macfadyen), picks up comely young socialite Caroline Cushing (Rebecca Hall) in a 747’s first-class cabin on his way to California to meet Nixon for the first time — adroitly conveys the gifted gabber’s talent for mixing work and pleasure.

The only slightly disconcerting aspect of Sheen’s turn is his appearance; with his longish, brushed-back hair, sideburns, arched eyebrows and occasionally pursed lips, he calls to mind Jack Nicholson in “The Shining.” For her part, as coiffed here, Hall looks quite like Carly Simon.

Widely viewed as a lightweight ill equipped to take on a cagey old pro like Nixon, Frost engages two key associates to help strategize for the big event, vet journo Bob Zelnick (Oliver Platt) and professional Nixon hater James Reston (Sam Rockwell). Nixon, portrayed as leading a lonely, isolated life at his seaside villa in San Clemente (key location work was done at the president’s actual house, Casa Pacifica), relies for support on a former Marine, Col. Jack Brennan (Kevin Bacon), while wife Pat (Patty McCormack, child star of “The Bad Seed”) putters around in a fog.

While the preliminaries could have been served up with a bit more panache, the behind-the-scenes details prove more interesting than might have been imagined. Reston, especially, senses that Frost, who’s consumed by trying to nail down backing for the $2 million undertaking, will fail to put Nixon through “the trial he never had” and supply what he feels the American people need — a conviction.

Dramatic intensity increases when the interviews commence at pic’s midway point. The interviews were taped, not at Nixon’s own abode, but at the modest nearby home of a Republican Party supporter. Nixon has his way with Frost through the first three sessions, telling long stories, reinforcing his presidential stature and digressing when his interlocutor attempts to put him on the spot.

The interview excerpts are obviously the real thing, and have been staged with great attention to how they actually looked. Where the script really shines is in the incidental backstage conversation, especially how Nixon smalltalks with Frost and catches him off-guard with remarks about the host’s presumed sex life and habits. These private exchanges culminate in the work’s most compelling sequence, in which an inebriated Nixon, prior to the final interview, phones Frost with a late-night ramble stressing their perceived similarities as fellows from modest circumstances looked down upon by “the snobs.”

By the final scenes, Langella has all but disappeared so as to deliver Nixon himself, leading to a melancholy ending defined, as predicted, by the triumph of one man and the virtual vanquishing of the other.

Playing real-life participants, some better known than others, supporting players are uniformly effective. A host of locations, including the very suite at the Beverly Hilton where Frost stayed, heighten the verisimilitude, although production designer Michael Corenblith, his staff and costume designer Daniel Orlandi have advisedly soft-pedaled the mid-’70s accoutrements so as not to distract too much from serious matters at hand. Hans Zimmer’s background score provides some extra zing, while the R rating, earned no doubt by a number of vulgarities, is unfortunate, as it will further limit the number of younger people who might see the film.